Cisco Catalyst 4500 Series, Software Configuration Manual

Page: 871 / 2086

C H A P T E R
30-1
Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
30
Configuring 802.1Q Tunneling, VLAN Mapping,
and Layer 2 Protocol Tunneling
Virtual private networks (VPNs) provide enterprise-scale connectivity on a shared infrastructure, often
Ethernet-based, with the same security, prioritization, reliability, and manageability requirements of
private networks. Tunneling is a feature designed for service providers who carry traffic of multiple
customers across their networks and who are required to maintain the VLAN and Layer 2 protocol
configurations of each customer without impacting the traffic of other customers. This chapter describes
how to configure 802.1Q, Layer 2 protocol tunneling, and VLAN mapping (or VLAN ID translation) on
a Catalyst 4500 series switch.
This chapter contains these sections:
•
About 802.1Q Tunneling, page 30-1
•
Configuring 802.1Q Tunneling, page 30-3
•
About VLAN Mapping, page 30-6
•
Configuring VLAN Mapping, page 30-9
•
About Layer 2 Protocol Tunneling, page 30-13
•
Configuring Layer 2 Protocol Tunneling, page 30-15
•
Monitoring and Maintaining Tunneling Status, page 30-23
Note
For complete syntax and usage information for the switch commands used in this chapter, see the
Cisco IOS Command Reference Guides for the Catalyst 4500 Series Switch .
If a command is not in the Cisco Catalyst 4500 Series Switch Command Reference , you can locate it in
the Cisco IOS Master Command List, All Releases .
About 802.1Q Tunneling
The VLAN ranges required by different customers in the same service provider network might overlap,
and customer traffic through the infrastructure might be mixed. Assigning a unique range of VLAN IDs
to each customer restricts customer configurations and could easily exceed the VLAN limit (4096) of
the 802.1Q specification.
802.1Q tunneling enables service providers to use a single VLAN to support customers who have
multiple VLANs, while preserving customer VLAN IDs and keeping traffic in different customer
VLANs segregated.